The present invention relates to the field of continuous ink jet printing and, more particularly, to the flushing of one ink from a fluid system when replacing it with one of a different color or chemistry.
Continuous ink jet printers are a substantial capital investment for a printing company. It is therefore desired to maximize the time available for such a system to print. A printer may have a variety of printing jobs, each requiring a different ink. Ink choice may be based on color, permanence or ease of operation. It is therefore desirable that the ink in a continuous ink jet printer may be easily changed, instead of dedicating a printer to each type of ink.
As ink chemistry, in addition to color, may be incompatible between inks, it is desirable to flush the system with a colorless fluid of low surface tension to remove and dilute the old ink, then introduce the new ink.
Existing art requires the operator to perform such tasks as draining the old ink and flush fluid by inserting a tube into a fitting while holding a bucket as the tank drains, disposing of these buckets of waste, and connecting a special manifold in place of the printhead to properly route the fluid. The flush fluid is then circulated and disposed. No provision is made to remove ink trapped in tubing by sending it directly to waste. The flush instead works by successive dilutions of the residual ink.
Another option is to attach a flush system, consisting of tanks of flush fluid, pumps and a waste tank. This involves extra expense for the customer in purchasing the flush system, and the disadvantage of only flushing one fluid system at a time with the flush system.
It is therefore an object of the present invention to provide a means of flushing and changing the ink in a continuous ink jet fluid system.
It is a further object of the present invention to have the flushing include the printhead(s) in a system.
It is yet another object of the present invention to accomplish the flushing with a minimum of auxiliary equipment.
These objects are met by the fluid system flush technique according to the present invention.
In accordance with one aspect of the present invention, the fluid flush system flushes residual ink from a fluid system to facilitate an ink change. The fluid system may be configured with one or more printheads. In accordance with the present invention, a common flush system is provided to serve all printheads in the multiple printhead configuration. The separate plumbing within each printhead interface controller (PIC) and printhead is, therefore, substantially identical.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.